And as I'm going to do many times in 3.091, I'm going to start a unit like this with a history lesson.

在3。091这门课上我会重复很多次，我会像现在一样以一个历史的故事,来开始新的一单元。

麻省理工公开课 - 固态化学导论课程节选

So for some you that are less interested in maybe the physical structure of an individual atom, now some more exciting material for you might be coming up if you like to think about how, instead, molecules behave, either within bonding, within themselves, or with other molecules, that's what we're going to be heading to in this next unit.

那么对于某些同学，你们或许不感兴趣,对于单个原子的物理结构，现在可能有令你感到兴奋的内容,要出现了，如果你更喜欢思考,分子的行为，或者是关于成键的，或者是关于它们本身的，又或者与其它分子之间的行为，这些将是我们下个单元要讲的内容。

麻省理工公开课 - 化学原理课程节选

So the repeating unit in DNA is this structure here, a nucleotide, which has three different regions.

NA的重复单位就是,核苷酸,它有三个不同的区域

耶鲁公开课 - 生物医学工程探索课程节选

Every unit in the backbone of this ladder has the same sugar unit, the same pentose; it's either RNA or DNA and has ribose or deoxyribose, so you don't need to describe the whole thing.

主链的每个单位,都由相同的糖单位构成,同样的戊糖,RNA里是核糖,DNA里是脱氧核糖,所以你不需要所有细节都描述

耶鲁公开课 - 生物医学工程探索课程节选